Biological Control with Insects: The Alligatorweed Flea Beetle

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Material Information

Title:
Biological Control with Insects: The Alligatorweed Flea Beetle
Physical Description:
Fact sheet
Creator:
Center, Ted D.
Publisher:
University of Florida Cooperative Extension Service, Institute of Food and Agriculture Sciences, EDIS
Place of Publication:
Gainesville, Fla.
Publication Date:

Notes

Acquisition:
Collected for University of Florida's Institutional Repository by the UFIR Self-Submittal tool. Submitted by Melanie Mercer.
Publication Status:
Published
General Note:
"Revised: November 1997. Revised: May 2002"
General Note:
"SS AGR 133"

Record Information

Source Institution:
University of Florida Institutional Repository
Holding Location:
University of Florida
Rights Management:
All rights reserved by the submitter.
System ID:
IR00004562:00001


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SS-AGR-133 Biological Control with Insects: The Alligatorweed Flea Beetle 1 Ted D. Center, F. Allen Dray, and Vernon V. Vandiver, Jr.2 1. This document is SS AGR 133, one of a series of the Department of Agronomy, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Revised: November 1997. Revised: May 2002. Please visit the EDIS Web site at http://edis.ifas.ufl.edu. 2. Ted D. Center, Research Entomologist, USDA Agricultural Research Service, Invasive Plant Research Laboratory, Fort Lauderdale, FL 33314; F. Allen Dray, Ecologist, USDA Agricultural Research Service, Invasive Plant Research Laboratory, Fort Lauderdale, FL 33314; and Vernon V. Vandiver, Associate Professor and Extension Aquatic Weeds Specialist, Fort Lauderdale Research and Education Center, Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL 32611. The Institute of Food and Agricultural Sciences is an equal opportunity/affirmative action employer authorized to provide research, educational information and other services only to individuals and institutions that function without regard to race, color, sex, age, handicap, or national origin. For information on obtaining other extension publications, contact your county Cooperative Extension Service office. Florida Cooperative Extension Service/Institute of Food and Agricultural Sciences/University of Florida/Christine Taylor Waddill, Dean. ( Agasicles hygrophila Selman and Vogt Coleoptera: Chrysomelidae: Halticinae) Host : Alternanthera philoxeroides (Mart.) Griseb. (Amaranthaceae) The alligatorweed flea beetle was the first insect ever studied for biological control of an aquatic weed. The introduction of this insect into the U.S. was approved during 1963 but it was not successfully established until 1965. The first successful release was made at the Ortega River near Jacksonville during April 1965. Most of the beetles later released elsewhere were progeny of this population. These were originally obtained from the Ezeiza Lagoon near Buenos Aires, Argentina. This has been an extremely effective biological control agent in coastal regions but less so in inland, northern areas where winter temperatures eliminate the emergent portions of alligatorweed during the colder months and where the summers are hot and dry. Both adults and larvae feed on leaves often defoliating the stems. After the leaves are nearly gone, they even chew the epidermis from the stems. The adult flea beetles measure 5 to 7 mm long and about 2 mm wide. The shiny adults have a black head and thorax and black and yellow wing covers (elytra). The females deposit their eggs in masses on the undersides of alligatorweed leaves. Successful completion of the egg stage is contingent upon sustained high humidity. The eggs hatch in 4 days at diurnal temperatures between 20 to 30C (longer at cooler temperatures). Feeding damage by young larvae consists of circular pits less than 1 mm diameter in the lower surface of the leaf. The young larvae do not chew entirely through the leaf, but leave the upper surface intact. They prefer young leaves. At diurnal temperatures of 20 to 30C the developmental periods are 3 days, 2 days, and 3 days for the three respective instars, for a larval period of 8 days. After the larvae are fully grown they search for a suitable pupation site. They pupate within the hollow stem, so stem diameter is critical. The pupa is soft-bodied and uniformly pale cream in color. The pupational period is approximately 5 days.

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Biological Control with Insects: The Alligatorweed Flea Beetle 2 The female begins to lay eggs about 6 days after emergence. Oviposition continues for about 3 weeks during which time the average female lays 1127 eggs. In the Southeast, two population peaks (spring and fall) occur in the southernmost parts of their range whereas one (fall) occurs in more northerly areas. Alligatorweed flea beetles do not do well on "poor quality" alligatorweed (characterized by thin stems, short internodes, and abnormal coloration) or on terrestrial alligatorweed.